Test system and associated interface module

ABSTRACT

A module ( 44 ) for a test system interfaces between (a) a tester mechanism ( 16  and  42 ) having tester contacts ( 152 ) for carrying test signals and (b) a device-side board ( 46 ) having device-side contacts ( 162 ) for connection to external leads of an electronic device ( 40 ) under test. The interface module contains a tester side body ( 50 ) having tester side openings ( 86 ) for being positioned opposite the tester-side contacts, a device-side body ( 52 ) having device-side openings ( 136 ) for being positioned opposite the device-side openings, and interface conductors ( 54 ) extending through the tester-side and device-side openings for connecting the tester contacts to the device-side contacts. The tester body is configured, typically as at least five wedge-shaped portions ( 68 ), in such a manner as to enable the electronic device under test to have an increased number of external leads.

FIELD OF USE

This invention relates to test equipment, especially automated testequipment for testing and examining electronic devices such asintegrated circuits.

BACKGROUND ART

Integrated circuits (“ICs”) can be tested or/and examined in variousways. One testing/examining (diagnostic) technique is to electricallystimulate an IC and then monitor its electrical response, typically bycomparing the actual response to a reference response. Thestimulation/response-monitoring technique is commonly performed withautomated test equipment connected to the external electrical leads,commonly referred to as pins, by which the IC interacts with the outsideworld. The test equipment stimulates the IC by providing electricalsignals to the IC's pins and then monitoring the resultant electricalsignals provided from the IC on its pins.

Another diagnostic technique involves probing an IC, especially when theIC has failed and it is desirable to determine the reason(s) forfailure. The probing technique can be done in an intrusive manner byphysically contacting the IC with a probe. The probing technique canalso be done in a largely non-intrusive manner by directing radiationsuch as light, electrons, or ions toward parts of the IC. The testequipment which performs the stimulation/response-monitoring techniqueoften includes a probing capability.

FIG. 1 illustrates an example of a conventional test system thatcombines a stimulation/response-monitoring technique with anon-intrusive electron-beam probing capability for testing/examining anintegrated circuit 10 referred to generally as a device under test(“DUT”). The test system in FIG. 1 consists of core automated testequipment 12, manipulator 14, test head 16, tester load board 18,interface module 20, device-side board (or card) 22, and device chamber24 which contains an electron-beam probe (not separately shown). DUT 10is situated in device chamber 24 and attached to device-side board 22also situated in chamber 24.

An example of a test system containing automated test equipment 12,manipulator 14, and test head 16 is the Schlumberger ITS 9000® automatedtest system. An example of an electron-beam probe system containingdevice chamber 12 is the Schlumberger 10000® probe system. Module 20interfaces between the probe and test systems. Inasmuch as electron-beamprobing needs to be done in a high vacuum, interface module 20 isconfigured to be airtight along device-side board 22.

Interface module 20 consists of tester-side body 26, device-side body28, and electrical interface conductors 30 which pass through openings(not shown here) in bodies 26 and 28 to connect tester board 18 todevice-side board 22. Tester board 18, which electrically connects testhead 16 to interface conductors 30 along tester-side body 26, iscustomized to match head 16. Different implementations of board 18thereby permit interface module 20 to be utilized with differentversions of head 16. In the large majority of state-of-the-art testsystems that provide stimulation/response-monitoring capabilities, head16 and board 18 have outer lateral peripheries that are approximatelycircular in shape. Device-side board 22 which connects interfaceconductors 30 to the pins of DUT 10, is similarly customized for testingDUT 10. Different versions of board 22 enable module 20 to be employedwith different implementations of DUT 10.

During test operation, test equipment 12 generates electrical signalswhich are supplied through components 14, 16, 18, 20, and 22 tostimulate DUT 10. The resulting electrical response from DUT 10 is thenfurnished in the other direction through components 22, 20, 18, 16, and14 to test equipment 12 for evaluation. The electron-beam probe indevice chamber 24 non-intrusively probes DUT 10 to form an image of aportion of DUT 10. The probing may be done as test signals generated byequipment 12 are used to stimulate DUT 10.

One conventional example of interface module 20 suitable for interfacingan electron-beam probe system, such as the Schlumberger IDS 10000 probesystem, to a test system, such as the Schlumberger ITS 9000 test system,which provides a stimulation/response-monitoring capability is theSchlumberger 768 pin interface load module. FIG. 2a perspectivelyillustrates the Schlumberger 768 pin load module. FIG. 2b depictstester-side body 26 of the load module. FIG. 2c illustrates how themodule connects tester board 18 to device-side board 22. FIG. 2c alsodepicts the generally circular outer lateral periphery of tester board18.

Tester -side body 26 in the Schlumberger 768 pin load module containsfour physically separate tester-side portions 32 having tester-sideopenings through which interface conductors 30 pass. The tester-sideopenings are arranged in a pattern whose outer periphery is shapedgenerally like a square. See FIG. 2b. Device-side body 28 similarlycontains four physically separate device-side portions 34 havingdevice-side openings through which conductors 30 also pass. As indicatedin FIG. 2a, the device-side openings are arranged in a pattern whoseouter periphery is likewise shaped generally like a square. Althoughdifficult to see in FIGS. 2a and 2 b, conductors 30 protrudesufficiently far out of these openings to contact electrical contacts,e.g., metal pads, on boards 18 and 22.

Each device-side portion 34 is situated largely opposite a correspondingone of tester-side portions 32 to form a combination that utilizes onequarter of the total number, i.e., 768, of interface conductors 30 inthe Schlumberger 768 pin load module. Each combination of onetester-side portion 32, corresponding device-side portion 34, and theassociated quarter of interface conductors 30 can be removed as a unitfrom the Schlumberger 768 pin load module. This facilitates repairingthe load module should one of these units fail. However, the module hasonly 768 conductors 30 and thus is limited to use in testingimplementations of DUT 10 having no more than 768 pins.

ICs having more than 768 pins are being fabricated now and are expectedto become more prevalent in the future. Accordingly, it is desirable tohave a module which can accommodate considerably more than 768 pins asit interfaces between a non-intrusive probe system and an automated testsystem having a stimulation/response-monitoring capability. It is alsodesirable that such an interface module be easy to repair.

GENERAL DISCLOSURE OF INVENTION

The present invention furnishes an interface module which, wheninstalled in a test system, enables the system to test or/and examine anelectronic device, typically an integrated circuit, having a largenumber of external electrical leads, e.g., pins. The module of theinvention is suitable for interfacing between a state-of-the-artnon-intrusive probe system and a state-of-the-art test system thatprovides a stimulation/response-monitoring capability and, when utilizedin such an overall test system, can readily accommodate an IC havingconsiderably more than 768 pins. The present interface module is alsotypically configured to facilitate module repair.

More particularly, an interface module in accordance with the inventionis intended to be situated between (a) a test mechanism having multipleelectrical tester contacts for carrying test signals and (b) adevice-side board (or card) having multiple electrical device-sidecontacts for connection to external electrical leads of an electronicdevice, such as an IC, under test. The test signals may include powersupply signals. The interface module contains a tester-side body, adevice-side body, and a group of electrical interface conductors.

The tester-side body of the present interface module normally containsat least five physically separate generally wedge-shaped tester-sideportions laterally arranged so that their tips are directed generallytoward one another. The number of wedge-shaped tester-side portions isnormally a multiple of four, eight being the lowest such multiple. Eachtester-side portion has multiple tester-side openings suitable for beingpositioned opposite corresponding ones of the tester contacts of thetest mechanism.

The device-side body of the interface module has multiple device-sideopenings suitable for being positioned opposite the device-side contactsof the device-side board. Each interface conductor extends through oneof the tester-side openings and through a corresponding one of thedevice-side openings for connecting one of the tester-side contacts to acorresponding one of the device-side contacts.

The tester-side openings in the tester-side body are preferably arrangedin a pattern whose outer periphery is shaped generally like a circle ora polygon having at least five sides. In the case of a polygon, eachside of the polygon corresponds to a different one of the tester-sideportions. Multiple ones of the tester-side openings in each tester-sideportion define the corresponding side of the polygon. The polygon istypically a regular polygon, i.e., a polygon whose sides are of equallength and whose angles are of equal value.

As mentioned above, both the test head and the adjoining tester board inthe large majority of state-of-the-art automated test systems whichprovide stimulation/response-monitoring capabilities have outer lateralperipheries of generally circular shape. As a result, the area availablefor tester-side openings in an interface module adjoining the testerboard is typically approximately circular in shape. However, the outerperiphery of the pattern of tester-side openings in the tester-side bodyof the conventional interface module described above in connection withFIGS. 2a-2 c is generally square shaped. Hence, the tester-side body ofthe conventional interface module does not utilize all of the areaavailable for tester-side openings in a test system where the part ofthe test system adjoining the tester-side body is generally circular inshape.

A regular polygon which has five or more sides and which is situatedinside a given circular area so that the polygon's sides all touch theperiphery of the circular area occupies a greater fraction of thecircular area than does a square situated in the circular area so thatthe square's sides likewise all touch the periphery of the circulararea. By arranging the tester-side openings in the tester-side body ofthe present interface module to be in a pattern whose outer periphery isshaped generally like a circle or a regular polygon having five or moresides, the tester-side body of the present module can readily utilizemore of the normally circular area available for tester-side openingsthan does the tester-side body of the conventional interface moduledescribed above. Consequently, the tester-side body of the presentinterface module can readily have more, often considerably more,tester-side openings than the conventional interface module withoutincreasing the areal density of the tester-side openings.

As also indicated above, each interface conductor in the presentinterface module passes through one of its device-side openings on theway to contacting one of the device-side contacts of the device-sideboard. Since the present module can have an increased number oftester-side openings relative to the conventional interface moduledescribed above, the device-side board can also have an increased numberof device-side contacts. Accordingly, the interface module of theinvention normally enables the test system to test/examine an electronicdevice having more external electrical leads than can be examined in atest system utilizing the conventional interface module.

The device-side body of the present interface module normally containsat least five physically separate device-side portions respectivelycorresponding to the tester-side portions of the tester-side body. Eachdevice-side portion has multiple ones of the device-side openings. Theinterface module is arranged so that one of the interface conductorspasses through one of the device-side openings of each device-sideportion and then through one of the tester-side openings of thecorresponding tester-side portion. Each tester-side portion, thecorresponding device-side portion, and the associated interfaceconductors preferably form a unit which is removable from the interfacemodule separately from each other such unit. This removabilitycharacteristic enables the module to be repaired easily.

The interface module of the invention can be modified in various ways.In one variation, the tester-side body can have as few as two physicallyseparate tester-side portions which are laterally arranged so that theirouter lateral peripheries are, as a group, shaped generally like acircle. The remainder of the interface module is arranged generally asdescribed above except that the device-side body can similarly have asfew as two physically separate device-side portions respectivelycorresponding to the tester-side portions. This variation enables thetest system to test/examine an electronic device having an increasednumber of external electrical leads while still facilitating repair ofthe module.

The present invention also furnishes a test system for testing or/andexamining an electronic device such as an IC. The test system contains atest mechanism, an interface module, and a device-side board allgenerally configured as specified above in connection with the presentinterface module. The test mechanism preferably includes a test head anda tester board attached to the test head. The tester board has thetester contacts which contact the interface conductors of the interfacemodule. By customizing the test board to the characteristics of the testhead, the interface module of the invention can be utilized withdifferent versions of the test head.

The present test system normally includes a probe for probing the deviceunder test in a largely non-intrusive manner. The probe is preferablypositioned so as to probe the device under test from an oppositelocation to where the device-side board receives the device under test.In a preferred implementation, the device-side body of the interfacemodule is physically coupled to the tester-side body substantially onlythrough electrical interface conductors that pass through openings inthe testers and device-side bodies. This largely isolates the probe fromthe test mechanism. Consequently, vibrations that may occur in the testmechanism are largely prevented from being transmitted to the probe anddisturbing its diagnostic function.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a conventional test system.

FIG. 2a is a perspective view of a conventional interface moduleemployed in the test system of FIG. 1.

FIG. 2b is a plan view of the tester side of the interface module ofFIG. 2a.

FIG. 2c is a perspective view of the interface module of FIG. 2a as thatmodule is positioned between the tester and device-side boards in thetest system of FIG. 1.

FIG. 3 is a block diagram of a test system according to the invention.

FIG. 4 is a perspective view of an interface module, excluding themodule's electrical interface conductors, configured according to theinvention for usage in the test system of FIG. 3.

FIGS. 5 and 6 are tester-side and device-side views of the interfacemodule of FIG. 4.

FIG. 7 is an exploded perspective view of the interface module, againexcluding the interface conductors, of FIG. 4.

FIG. 8 is a perspective view of the interface module, now including theinterface conductors, of FIG. 4.

FIGS. 9 and 10 are enlarged perspective views of parts of thetester-side and device-side bodies of the interface module of FIG. 4.

FIGS. 11 and 12 are tester-side and device-side photographs of theinterface module of FIG. 4.

FIG. 13 is a schematic side cross-sectional view of part of theinterface module of FIG. 4 as that module is positioned between thetester and device-side boards in the test system of FIG. 3.

FIG. 14 is a schematic side cross-sectional view of part of oneinterface conductor as it passes through the interface module of FIG. 4.

Like reference symbols are employed in the drawings and in thedescription of the preferred embodiments to represent the same, or verysimilar, item or items.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 3 illustrates a test system configured in accordance with theinvention for testing or/and examining an electronic device 40. The testsystem of FIG. 3 furnishes a digital test capability and, optionally, ananalog test capability. Hence, DUT 40 can be a digital device or,optionally, a device having both digital and analog (mixed-signal)circuitry. By suitably implementing the test system of FIG. 3, DUT 40can also be solely an analog device.

Compared to the situation in which interface module 20 in theconventional test system of FIG. 1 is implemented with the Schlumberger768 pin load module, the test system of FIG. 3 is configured to enableDUT 40 to have considerably more external electrical leads than DUT 10.In one embodiment, DUT 40 can have up to 1024 external electrical leadsfor transmitting digital signals and, depending on the power supplyrequirements of DUT 40, often slightly more than 1024 externalelectrical leads for transmitting digital signals. DUT 40 is typicallyan IC. However, DUT 40 can be another type of electronic device such asa multi-chip module.

The inventive test system of FIG. 3 consists of core automated testequipment 12, manipulator 14, test head 16, a tester load board 42, aninterface module 44, a device-side board (or card) 46, and a devicechamber 48 which contains a non-intrusive probe (not separately shown).Analogous to where DUT 10 and device-side board 22 are located in theconventional test system of FIG. 1, DUT 40 here is situated in devicechamber 48 and attached to device-side board 46 also situated in chamber48. The non-intrusive probe in chamber 48 can function by directingelectrons toward DUT 40 in a manner similar to how the electron-beamprobe operates in the test system of FIG. 1. The non-intrusive probe inthe test system of FIG. 3 can also direct other type of radiation, suchas light or ions, toward DUT 40. To enable a non-intrusive probe thatrequires a high vacuum to be utilized in device chamber 48, interfacemodule 44 is normally airtight along device-side board 46.

Interface module 44 is configured according to the invention forenabling DUT 40 to have the above-mentioned increased number of externalelectrical leads, e.g., pins when DUT 40 is an IC, for transmittingdigital signals. Interface module 40 contains a tester-side body 50, adevice-side body 52, and a group of digital-capability electricalinterface conductors 54. The number of digital-capability interfaceconductors 54 is normally slightly greater than the maximum number,e.g., 1024, of external electrical leads that DUT 40 has fortransmitting digital signals. Conductors 54 pass through openings (notshown here) in bodies 50 and 52 for electrically connecting tester-sidedigital-capability electrical contacts (also not shown here) of testerboard 42 respectively to device-side digital-capability electricalcontacts (likewise not shown here) of device-side board 46. When ananalog-capability is needed, module 44 also has a group ofanalog-capability electrical interface conductors (not shown here) thatpass through openings in bodies 50 and 52 for electrically connectingtester-side analog-capability electrical contacts of tester board 42respectively to device-side analog-capability electrical contacts ofdevice board 46.

Tester board 42 electrically connects test head 16 to digital-capabilityinterface conductors 54 and the optional analog-capability interfaceconductors along tester-side body 50. As with tester board 18 above,tester board 42 here is customized to match test head 16. Accordingly,different implementations of board 42 enable interface module 44 to beutilized with different versions of test head 16. Board 42 typically hasan approximately circular outer lateral periphery. Nonetheless, theouter lateral periphery can be substantially non-circular, e.g.,rectangular or, in particular, square.

Tester board 46 electrically connects digital-capability interfaceconductors 54 and the optional analog-capability interface conductors tothe external electrical leads of DUT 40. Similar to device-side board22, device-side board 46 is customized to match DUT 40. Differentversions of board 46 enable interface module 44 to be utilized withdifferent implementations of DUT 40.

Aside from the increased lead-handling capability provided by interfacemodule 44 and any test-equipment enhancements or other changes needed toaccommodate the increased lead-handling capability, components 12, 14,16, 42, 44, and 46 in the test system of FIG. 3 operate respectively thesame as components 12, 14, 16, 18, 20, and 22 in the test system of FIG.1. During test operation, test equipment 12 in the test system of FIG. 3thus generates electrical test signals which are furnished throughcomponents 14, 16, 42, 44, and 46 to stimulate DUT 40. The test signalsnormally include power supply signals. The resulting electrical responsefrom DUT 40 is furnished in the other direction through components 46,44, 42, 16, and 14 to test equipment 12 for evaluation.

The non-intrusive probe in device chamber 46 non-intrusively probes DUT40. Depending on how the non-intrusive probe is implemented, the probingoperation on DUT 40 can be performed anywhere from room pressure,typically 1 atmosphere, down to a high vacuum, e.g., 10⁻⁶ torr or lower.The non-intrusive probe is an electron-beam probe operated at a highvacuum according to a scanning-electron-microscope technique in oneembodiment. In that case, the test system of FIG. 3 combines anelectron-beam probe system, such as the Schlumberger IDS 10000 system,with automated test equipment, such as the Schlumberger ITS system,which provides a stimulation/response-monitoring test capability. Devicechamber 46 in the test system of FIG. 3 is then electron-beam probesystem 22 in the test system of FIG. 1. Interface module 20 can, ofcourse, be utilized with other non-intrusive probe systems and withother automated test equipment that implements components 12, 14, and16.

FIGS. 4-10 present various views, including partial views, of anembodiment of interface module 44 which enables DUT 40 to have up to1024 external electrical leads for transmitting digital signals and,optionally, up to 32 analog-capability external electrical leads fortransmitting analog signals. FIGS. 4-7, 9, and 10 variously illustratethe elements of module 40 except for digital-capability interfaceconductors 54 and the optional analog-capability interface conductors.Digital-capability conductors 54 are depicted in FIG. 8.

More particularly, FIG. 4 is a general perspective view of all ofinterface module 44 (except for digital-capability interface conductors54 and the optional analog-capability interface conductors). FIG. 5 is aplan view as seen from the tester side (top side in FIG. 3) of module44. FIG. 6 is a plan view as seen from the device side (bottom side inFIG. 3) of module 44. FIG. 7 is an exploded perspective view of module44. Except for the inclusion of digital-capability conductors 54, FIG. 8presents the same perspective view as FIG. 4. FIG. 9 is an enlarged viewof part of tester-side body 50. FIG. 10 is an enlarged view of part ofdevice-side body 52.

Tester-side body 50 in the example of FIGS. 4-10 consists of an annulartester-side main portion 60, three largely identical protective flanges62, a spider-shaped tester-side member 64, a circular cylindricaltester-side portion 66 utilized in providing the optional analog testcapability, and eight largely identical generally wedge-shapedtester-side portions 68 employed in providing the digital testcapability. Components 60, 62, 64, 66, and 68 are all formed with metal,typically an aluminum alloy, and are therefore electrically conductive.Cylindrical tester-side analog-capability portion 66 can be deleted fromtester-side body 50 if an analog test capability is not needed.

Tester-side main portion 60 has a circular outer lateral periphery andan upper inner lateral periphery roughly in the shape of a regularoctagon. The outside diameter of main portion 60 is 16-20 cm, typically18.4 cm. Protective flanges 62 protrude from the outside lateralperiphery of main portion 60 and are spaced approximately equidistantfrom one another. A circular opening 72 extends through each flange 62.

Spider-shaped member 64 consists of a central portion 72 and eightlargely identical ribs 74 extending laterally away from central portion72 at largely equal angles. A circular central opening 76 extendsthrough central portion 72. Each rib 74 widens partway along its lengthat a location where a mounting hole 78 extends through that rib 74. Thecenters of mounting holes 78 are situated on an imaginary circle havinga radius of 4-5 cm, typically 4.7 cm. Tester-side body 50 is physicallyconnected to tester board 42 by way of bolts inserted into mountingholes 78.

Ribs 74 narrow after passing mounting holes 78 in moving away from thecenter of spider-shaped member 64. Each rib 74 again widens near itsouter end. Member 64 is located inside the inner lateral periphery oftester-side main portion 60 and is attached to main portion 60 along anouter flange of each rib 74. Each attachment location, and thus theouter edge of each rib 74, occurs where two consecutive sides of theregular octagonal inner laterally periphery of main portion 60 meet.

Cylindrical analog-capability portion 66, when present, is situated incentral opening 76 of central portion 72 of spider-shaped member 64.Cylindrical portion 66 is attached to member 64 along a widened lowerpart of portion 66. Although attached to member 64, cylindrical portion66 is electrically insulated from member 64 and from other electricallyconductive parts of tester-side body 50 by way of electrical insulation(not shown) situated around portion 66. As described further below,cylindrical portion 66 receives ground potential from theanalog-capability interface conductors during test operation.

37 equal-size tester-side analog-capability openings 80 extend throughcylindrical portion 66. 40 equal-size tester-side analog-ground openings82 extend partway into cylindrical portion 66 along its top side. SeeFIG. 5. Tester-side analog-ground openings 82 are of considerablysmaller average diameter than tester-side analog-capability openings 80.Analog-ground openings 82 are distributed in such a way that at leasttwo openings 82 are directly adjacent to each analog-capability opening80. Each analog-ground opening 82 contains an analog-ground pindiscussed below.

A wedge has a plane shape in which three lines, referred to here as thebase and the two sides, meet each other at angles. The two sides of thewedge are straight and typically of the same, or close to the same,length. The base of the wedge can be straight. In that case, the wedgeis an isosceles triangle. The wedge's base can also be curved. If thebase is circularly curved in a convex manner relative to the sides ofthe wedge, the wedge has the form of a piece of pie.

In the example of FIGS. 4-10, each wedge-shaped digital-capabilityportion 68 is roughly shaped like an isosceles triangle. Moreparticularly, each portion 68 in the embodiment of FIGS. 4-10 is shapedlike the vertical profile of a pine tree, i.e., like an isoscelestriangle except that the two sides of the triangle are replaced withwavy lines. As described further below, the base of each portion 68 canbe significantly curved, typically circularly curved in a convex mannerso that each portion 68 is roughly shaped like a piece of pie.

The combination of tester-side main portion 60 and spider-shaped member64 defines eight largely identical generally wedge-shaped openings 84whose tips are directed toward the center of tester-side main portion 60and thus toward one another. Wedge-shaped openings 84 are of largely thesame size and shape as wedge-shaped portions 68. Consequently, eachopening 84 in the embodiment of FIGS. 4-10 is roughly shaped like anisosceles triangle or, more specifically, like the vertical profile of apine tree.

Each of wedge-shaped portions 68 fits snugly into a corresponding(different) one of wedge-shaped openings 84. Accordingly, portions 68are laterally arranged so that their tips are directed toward the centerof main portion 60 and thus toward one another. Ribs 74 of spider-shapedmember 72 physically separate portions 68 from one another. Becauseportions 68 are roughly shaped like isosceles triangles or, moreparticularly, like the vertical profiles of pine trees, the outerlaterally peripheries of portions 68 are, as a group, shapedapproximately like a regular octagon. Even more particularly, portions68 form, as a group, an annular pattern having a generally circularinner periphery and a roughly octagonal outer periphery since portions68 laterally surround circular cylindrical portion 66.

Each wedge-shape portion 68 is attached to spider-shaped member 64 alongthe two adjacent ones of ribs 74. In particular, each portion 68 has twoflanges which protrude outward along the base of that portion 68 andwhich are attached to the outer flanges of the two adjacent ribs 74.Each portion 68 also has an additional flange located near the tip ofthat portion 68 and attached to an additional flange of one of the twoadjacent ribs 74.

Wedge-shaped portions 68 are electrically connected to one anotherthrough spider-shaped member 64. As described further below, portions 68receive ground potential from digital capability interface conductors 54during test operation. Consequently, portions 68 are at a common digitalground potential during test operation. Inasmuch as cylindricalanalog-capability portion 66 is electrically insulated from otherelectrically conductive parts of tester-side body 50 and thus fromwedge-shaped portions 66, the analog ground on cylindrical portion 66 isisolated from the common digital ground on wedge-shaped portions 68.

Importantly, wedge-shaped portions 68 closely match the lateral contoursof ribs 74. Each portion 68 has a pair of notches (or lateraldepressions) where the two adjoining ribs 74 widen partway along theirlengths. These notches in the sides of portions 68 and the widenedportions of ribs 74 enable portions 68 to be positioned very accuratelyin wedge-shaped openings 82. The alignment of portions 68 to mountingholes 78, and thus to tester board 42, is excellent.

140 equal-size tester-side digital-capability openings 86 extend througheach wedge-shaped portion 68. Tester-side digital-capability openings 86of each portion 68 are distributed across largely all of that portion 68to form an annular pattern whose outer lateral periphery is roughlywedge shaped. Accordingly, the outer lateral periphery of the pattern ofopenings 86 in each portion 68 in the example of FIGS. 4-10 is roughlyshaped like an isosceles triangle or, more particularly, like thevertical profile of a pine tree. In any event, the base of thewedge-shaped outer lateral periphery of the pattern of openings 86 ineach portion 68 is largely straight in the example of FIGS. 4-10.

Tester-side digital-capability openings 86 are arranged in rows andcolumns in each wedge-shaped portion 68. The row/column arrangement canbe clearly seen in FIG. 9. The columns of openings 86 in each portion 68extend parallel to one another and parallel to the longitudinal axis 88of that portion 68. Longitudinal axes 88 all intersect at the center oftester-side main portion 60. The number of openings 86 in each column ofopenings 86 in each portion 68 decreases generally in moving away fromlongitudinal axis 88 of that portion 68. The rows of openings 86 extendparallel to one another and perpendicular to the columns of openings 86.Except near the base of each portion 68, the number of openings 86 ineach row of openings 86 in that portion 68 decreases generally in movingaway from the base of that portion 68 toward its tip.

Digital-capability openings 86 in each wedge-shaped portion 68 aredistributed in a relatively uniform manner across that portion 68.Accordingly, the spacing between consecutive columns of openings 86 ineach portion 68 is largely the same. Likewise, the spacing betweenconsecutive rows of openings 86 in each portion 68 is largely the same.The inter-row spacing also approximately equals the inter-columnspacing. The density of openings 86 in each portion 68 is 2-4openings/cm², typically 3 openings/cm².

Digital-capability openings 86 in each pair of consecutive columns, orgenerally center-directed longitudinal lines, of openings 86 in eachwedge-shaped portion 68 are staggered relative to one another. Inparticular, each column of openings 86 is formed with openings 86 fromalternative rows of openings 86. Openings 86 in each pair of consecutiverows, or transverse lines, of openings 86 in each portion 68 aresimilarly staggered relative to one another.

The total number of digital-capability openings 86 is 1120, i.e., 140times 8, the number of wedge-shaped portion 68. Since the base of thewedge-shaped outer lateral periphery of the pattern of openings 86 ineach portion is largely straight in the example of FIGS. 4-10, the 1120openings 86 are, as a group, arranged in a pattern whose outer lateralperiphery is shaped roughly like a regular octagon in the example ofFIGS. 4-10. Each side of the octagon is formed by the base of thewedge-shaped outer lateral periphery of the pattern of openings 86 in acorresponding one of portions 68. Multiple ones, eight in the example ofFIGS. 4-10, of openings 86 in each portion 68 define the correspondingside of the octagon.

In addition to digital-capability openings 86, 173 equal-sizetester-side digital-ground openings 90 extend partway into eachwedge-shaped portion 68 along its top side. See FIGS. 5 and 9.Tester-side digital-ground openings 90 are of considerably smalleraverage diameter than openings 86. Digital-ground openings 90 arearranged in rows and columns in the same way as openings 86. Four ofdigital-ground openings 90 are directly adjacent to eachdigital-capability opening 86. Each digital-ground opening 90 contains adigital-ground pin discussed below.

Rather than being generally straight, the base of each wedge-shapedportion 68 can be significantly curved, typically circularly curved in aconvex manner. When the bases of portions 68 are generally circularlycurved in a convex manner, the outer lateral periphery of portions 68are, as a group, shaped approximately like a circle. In that case, theouter lateral periphery of the pattern of digital-capability openings 86in each portion 68 can be shaped roughly like a piece of a pie. Theouter lateral periphery of the pattern of all of openings 86 is, as agroup, then shaped roughly like a circle. Arranging portions 68 andopenings 86 in this manner may enable the total number of openings 86 tobe increased further without changing the areal density of openings 86.

Device-side body 52 in the embodiment of FIGS. 4-10 consists of adevice-side main portion 100, three largely identical protective posts102, an L-shaped pipe fitting 104, eight generally rectangular-shapeddevice-side portions 106 utilized in providing the optional analog testcapability, eight generally right-trapezoidal-shaped device-sideportions 108 employed in providing the digital test capability, eightroughly rectangular sealing rings 110, eight roughly right-trapezoidalsealing rings 112, and a largely square sealing ring 114. Components100, 102, 104, 106, and 108 are formed with metal, typically an aluminumalloy, except possibly for pipe fitting 104 and the screws and washersused in protective posts 102. Accordingly, components 100, 102, 106, and108 are electrically conductive. Sealing rings 110, 112, and 114, whichonly appear in FIG. 6, consist of suitable rubber or rubber-like sealingmaterial.

Protective posts 102 are attached to the top of device-side main portion100 at locations approximately equidistant from one another andrespectively opposite openings 70 in flanges 62 of tester-side body 50.Each post 102 consists of a lower circular cylindrical section 120, anupper circular cylindrical section 122 continuous with lower section120, and a washer/screw combination 124 attached to the top of uppersection 122 by the screw. Lower sections 120 are of significantlygreater diameter than openings 70, whereas upper sections 122 are ofsignificantly lesser diameter than openings 70. Upper sections 122 arerespectively situated in openings 70 in such a way that posts 72 do nottouch flanges 62 when interface module 44 is situated in an uprightposition and no disturbance is applied to module 44.

The combination of flanges 62 and protective posts 102 protectsinterface module 44 by preventing its shape from being distendedsignificantly while module 44 is being handled. During normal testoperation, flanges 62 do not touch posts 102. Consequently, vibrationsthat may occur in tester components 12, 14, and 16 are not transmittedto device-side body 52, device-side board 46, or DUT 40 through flanges62 and posts 102.

Pipe fitting 104, shown in FIGS. 4, 5, and 8 but omitted from FIG. 7, ismounted on top of device-side main portion 100 and extends into anopening 105 which extends through main portion 100. FIG. 6 depictsopening 105. A vacuum pump is attached to fitting 104 when devicechamber 48 is to be operated at high vacuum. The cavity between mainportion main portion 100 and tester board 46 is pumped down by way ofpipe fitting 104 and opening 105 to assist in reaching the high vacuumneeded in chamber 48.

A group of holes 128 pass through device-side main portion 100 near itsouter lateral periphery. Device-side body 52 is physically connected todevice chamber 48 by way of bolts or screws inserted into selected onesof holes 128. A further group of holes 130 extend partway through mainportion 100 from its bottom side. See FIG. 6. Holes 130 are arranged ina roughly square pattern and are situated outside the location,discussed further below, of device-side analog-capability portions 106and device-side digital-capability portions 108. Device-side board 46 isattached to device-side body 52 by way of screws inserted through holesin board 46 and then into holes 130.

Rectangular-shaped analog-capability portions 106 are attached todevice-side main portion 100 and arranged in an annular pattern ofapproximately square shape. Rectangular-shaped portions 106 are alsosituated in eight respective openings extending through main portion 100opposite part of the location for device-side board 46. Each ofrectangular-shaped sealing rings 110 surrounds the lateral periphery ofa corresponding one of portions 106 along the bottom of main portion 100so as to provide a hermetic seal between that rectangular-shaped portion106 and device-side board 46. Although attached to main portion 100,rectangular-shaped portions 106 are electrically insulated from oneanother and from other electrically conductive parts of device-side body52 by way of electrical insulation (not shown) situated around eachportion 106. As described further below, portions 106 receive groundpotential from the analog-capability interface conductors during testoperation.

Four equal-size device-side analog-capability openings 132 extend in astraight line through each rectangular-shaped portion 106. See FIG. 6.Since there are eight portions 106, device-side body 52 has total of 32openings 132. As a result, interface module 44 can be utilized intesting implementations of DUT 40 having up to 32 analog-capabilityexternal electrical leads. In addition, five equal-size device-sideanalog-ground openings 134 of considerably smaller average diameter thananalog-capability openings 132 extend partway into each portion 106along its bottom side. Each analog-capability opening 132 lies between apair of analog-ground openings 134 in each portion 106. Eachanalog-ground opening 134 contains an analog-ground pin discussed below.

Trapezoidal-shaped digital-capability portions 108 are attached todevice-side main portion 100 and arranged in a roughly square annularpattern situated outside the annular square pattern ofrectangular-shaped portions 106. Four of trapezoidal-shaped portions 108are largely identical to one another and are largely mirror images ofthe other four largely identical portions 108. Two mirror-image portions108 form each side of the square annular pattern of portions 108. Theslanted sides of portions 108 are at the corners of the pattern. Thebase, i.e., the longer of the two parallel sides, of the trapezoidroughly defined by each portion 108 is at the outside of the pattern.

Trapezoidal-shaped portions 108 are also situated in eight respectiveopenings extending through tester-side main portion 100 opposite part ofthe location for tester board 46. Each of sealing rings 112 surroundsthe lateral periphery of a corresponding one of portions 108 along thebottom side of main portion 100 so as to provide a hermetic seal betweenthat portion 106 and board 46.

Trapezoidal-shaped portions 108 are electrically connected to each otherthrough tester-side main portion 100. As described further below,portions 108 receives ground potential from digital-capability interfaceconductors 54 during test operation. Accordingly, portions 108 are at acommon digital ground potential during test operation. Sincerectangular-shaped analog-capability portions 106 are electricallyinsulated from other electrically conductive parts of device-side body52 and thus from trapezoidal-shaped portions 108, the analog ground oneach rectangular-shaped portion 106 is isolated from the common digitalground on trapezoidal-shaped portions 108.

140 equal-size device-side digital-capability openings 136 extendthrough each trapezoidal-shaped portion 108, Digital-capability openings136 of each portion 108 are distributed across largely all of thatportion 108 to form a pattern whose outer laterally periphery is shapedroughly like a right trapezoid.

Digital-capability openings 136 are arranged in rows and columns in eachtrapezoidal-shaped portion 108. The row/column arrangement of openings136 can clearly be seen in FIG. 10. The rows of openings 136 in eachpair of portions 108 which define one side of the square annular patternformed by portions 108 extend parallel to that side of the pattern. Thecolumns of openings 136 extend parallel to the rows. The number ofopenings 136 in each row of openings 136 of each portion 108 generallydecreases in moving from the base of its trapezoidal shape toward thecenter of tester-side main portion 100. Openings 136 in each pair ofconsecutive rows or consecutive columns of openings 136 in each portion108 are also staggered relative to one another.

Digital-capability openings 136 in each trapezoidal-shaped portion 108are distributed in a relatively uniform manner across that portion 108,The spacing between consecutive rows and between consecutive columns ineach portion 108 is largely the same. The density of openings 136 ineach portion 108 is 2-4 openings/cm², typically 3 openings/cm².

As with tester-side digital-capability openings 86, the total number ofdevice-side digital-capability openings 136 is 1120, i.e., 140 times 8,the number of device-side trapezoidal-shaped portions 108. The 1120openings 136 are, as a group, arranged in an annular pattern whose outerlateral periphery is shaped roughly like a square. Each side of thesquare is formed by the bases of the trapezoidal-shaped outer lateralperipheries of the patterns of openings 136 in two adjacentcorresponding mirror-image portions 108. Multiple ones, 16 in theexample of FIGS. 4-10, of openings 136 in each portion 108 define onehalf of the corresponding side of the square.

178 equal-size device-side digital-ground openings 138 of considerablysmaller average diameter than device-side digital-capability openings136 extend partway into each trapezoidal-shaped portion 108 along itsbottom side. See FIGS. 6 and 10. Device-side analog-ground openings 138are arranged in rows and columns in the same manner asdigital-capability openings 136. Four of digital-ground openings 138 aredirectly adjacent to each digital-capability opening 136. Eachdigital-ground opening 138 contains a digital-ground pin discussedbelow.

Each of device-side trapezoidal-shaped digital-capability portions 108corresponds to a (different) one of tester-side wedge-shapeddigital-capability portions 68. There are typically 1120 ofdigital-capability interface conductors 54. 140 of the 1120digital-capability conductors 54 respectively extend from 140digital-capability tester electrical contacts (not shown here) of testerboard 42, through the 140 tester-side digital-capability openings 86 ofeach tester-side wedge-shaped portion 68, through the 140 device-sidedigital-capability openings 136 of corresponding device-sidetrapezoidal-shaped portion 108, and to 140 digital-capabilitydevice-side electrical contacts (not shown here) of device-side board46. See FIG. 8. The combination of device-side wedge-shaped portion 68,corresponding tester-side trapezoidal-shaped portion 108, and the 140interface conductors 54 which pass through openings 86 of that portion68 and openings 136 of that portion 108 form a unit 68/108/54 which canbe removed from interface module 44 separately from each of the otherseven such units 68/108/54.

128 of the 140 interface conductors 54 for each unit 68/108/54 areallocated for transmitting digital signals to and from 128 externalelectrical leads of DUT 40. There are eight units 68/108/54.Consequently, interface module 44 has 1024 conductors 54 allocated fordigital-signal transmission. The configuration of module 44 thereforeenable the test system of FIG. 3 to handle implementations of DUT 40having up to 1024 external electrical leads capable of transmittingdigital signals.

Eight of the remaining 12 interface conductors 54 for each unit68/108/54 are allocated for supplying power to DUT 40. The last four ofconductors 54 for each unit 68/108/54 are allocated for unspecifiedpurposes. Hence, a total of 64 conductors 54 are allocated for supplyingDUT 40 with power while a total of 32 conductors 54 are allocated forunspecified purposes. This allocation is somewhat arbitrary. Some of the64 conductors 54 allocated to supplying power can be utilized for otherpurposes, e.g., transmitting digital test signals, if less than 64conductors 54 are needed for supplying power to DUT 40.

Interface module 44 typically has 32 analog-capability electricalinterface conductors (not shown). These 32 analog-capability conductorsrespectively extend from 32 analog-capability tester-side electricalcontacts (not shown) of tester board 42, through 32 of the 37tester-side analog-capability openings 80 of cylindrical tester-sideportion 66, through the 32 device-side analog-capability openings 132 ofthe eight device-side trapezoidal-shaped portions 106, and to 32analog-capability device-side electrical contacts (not shown) ofdevice-side board 46. The configuration of interface module 44 thusprovides the test system of FIG. 3 with the optional capability tohandle implementations of DUT 40 having up to 32 external electricalleads for analog circuitry. The five unused analog-capability openings80 in tester-side 66 provide some capability for repairing portion 66and also some flexibility for modifying interface module 44 to add moreanalog-capability interface conductors if needed.

Along its bottom side, device-side main portion 100 has a centralroughly square recession 140 whose lateral periphery is indicated byline 142. See FIG. 6. Cavity 140 provides room for socket-mountinghardware and support componentry. Sealing ring 114 is situated along theoutside of all of device-side trapezoidal-shaped portions 108 over thenon-recessed part of main portion 100 along its bottom side so as toprovide a hermetic seal between device-side board 46 and the regionoccupied by rectangular-shaped portions 106 and trapezoidal-shapedportions 108. Along its bottom side, main portion 100 also has an outerperipheral recession 144 whose lateral extent is indicated by circle146. When device chamber 48 is to be operated at a pressure below roompressure, an O ring in chamber 48 meets the non-recessed part of mainportion 100 along circle 146 so as to hermetically seal device-side body52 of module 44 to chamber 48. The configuration of device-side body 52thus enables a high vacuum to be maintained in chamber 48.

FIGS. 11 and 12 present photographs of interface module 44 asrespectively seen from the tester side and the device side. Recessions140 and 144 can clearly be seen in FIG. 12.

Device chamber 48 may, or may not, be operated at a high vacuumdepending on how the non-intrusive probe is implemented. If thenon-intrusive probe utilizes electrons or ions to probe DUT 40, chamber48 is pumped down to a high vacuum, typically 10 ⁻⁶ torr or lower. Thevacuum in chamber 48 then causes device-side body 52 to be held stronglyto chamber 48. If the non-intrusive probe probes DUT 40 with light,e.g., in the form of a laser beam, chamber 48 can often be at roompressure. In that case, sealing rings 110, 112, and 114, can be deletedform interface module 44.

FIG. 13 presents a side cross section of part of interface module 44centered around one unit 68/108/54 for schematically illustrating howdigital-capability interface conductors 54 electrically contact testerboard 42 and device-side board 46. Boards 42 and 46 are illustrated verysimplistically in FIG. 13. Each board 42 and 46 is normally amulti-layer board having electrically conductive traces buried in theboard rather than a single-layer board as depicted in FIG. 13. As aresult, many of the metal interconnects shown as going fully throughboard 42 or 46 go only partway through board 42 or 46 when it is amulti-layer board. Each board 42 or 46 also typically has some metalinterconnects fully buried in the board. Furthermore, each via may onlybe partially filled with metal instead of being fully filled with metalas shown in FIG. 13.

Subject to the foregoing comments, simplified tester board 42 in FIG. 13consists of an electrically insulating main board 150, multiple testerdigital-capability electrical contacts 152 situated along the bottom ofmain board 150, multiple tester digital-ground electrical contacts 154likewise situated along the bottom of main board 150, multiple metalinterconnects 156 situated in vias extending through board 150, andelectrically conductive traces 158 situated on top of board 150.Digital-capability contacts 152 and digital-ground contacts 154 aremetal pads respectively electrically connected to metal interconnects156 which, in turn, are connected to conductive traces 158.

Subject to the same comments, simplified device-side board 46 in FIG. 13consists of an electrically insulating main board 160, multipledevice-side digital-capability electrical contacts 162 situated alongthe top of main board 160, multiple device-side digital-groundelectrical contacts 164 also situated along the top of main board 160,multiple metal interconnects 166 situated in vias extending throughboard 160, and electrically conductive traces 168 situated on the bottomof board 160. Digital-capability contacts 162 and digital-groundcontacts 164 are metal pads respectively electrically connected to metalinterconnects 166 which, in turn, are connected to conductive traces168.

Each digital-capability interface conductor 54 consists of an electricalcable 170, a tester-side metal pin 172 electrically connected to one endof cable 170, and a device-side metal pin 174 electrically connected tothe other end of cable 170. Cables 170 extend into digital-capabilityopenings 86 of tester-side wedge-shaped portions 68 and intodigital-capability openings 136 of device-side trapezoidal-shapedportions 108. Tester-side pins 172 respectively extend out ofdigital-capability openings 86 to electrically contact tester-sidedigital-capability contacts 152. Similarly, device-side pins 174respectively extend out of digital-capability openings 136 toelectrically contact device-side digital-capability contacts 162. Inaddition, tester-side metal pins 176 respectively extend out ofdigital-ground openings 90 of tester-side wedge-shape portions 68 toelectrically contact digital-ground contacts 154. Device-side metal pins178 similarly respectively extend out of digital-ground openings 138 ofdevice-side trapezoidal-shaped portions 108 to electrically contactdevice-side digital-ground contacts 164.

FIG. 14 presents a more detailed schematic cross section of how onedigital-capability interface conductor 54 is typically generallyimplemented to pass through a digital-capability opening 86 of onetester-side wedge-shaped portion 68 and electrically contact adigital-capability tester contact 152 of tester board 42 illustratedhere in the simplistic form utilized in FIG. 13. In this generalimplementation, cable 170 of illustrated interface conductor 54 is acoaxial cable formed with an inner metal signal conductor 180,intermediate annular electrical insulation 182 situated over signalconductor 180, an outer annular metal ground conductor 184 situated overinsulation 182, and outer electrical insulation 186 situated over groundconductor 184. Tester-side digital-capability metal pin 172, whichelectrically contacts illustrated tester contact 152, is a spring-loadedcontact that also electrically contacts signal conductor 180. Item 188in FIG. 14 indicates further electrical insulation which preventstester-side pin 172 from being electrically connected to metalwedge-shaped portion 68.

Cable 170 in the implementation of FIG. 14 also includes a spring-loadedcontact 190 which electrically connects ground conductor 184 toillustrated metal wedge-shaped portion 68. Tester-side digital-groundpin 176 is a spring-loaded contact in the implementation of FIG. 14.Ground conductor 184 carries a digital ground reference potential. Byemploying the arrangement of FIG. 14, the digital ground potential onground conductor 184 is transferred through spring-loaded contact 190,wedge-shaped portion 68, and spring-loaded pin 176 to a digital-groundcontact 154 on tester board 42. An arrangement largely identical to thatof FIG. 14 is typically utilized on the other end of interface conductor54 for electrically connecting signal conductor 180 and ground conductor184 respectively to a digital-capability device-side contact 162 and adigital-ground device-side contact 164.

The analog-capability interface conductors extend throughanalog-capability openings 80 in cylindrical tester-side portion 66 andthrough analog-capability openings 132 in the eight rectangular-shapeddevice-side portions 106 to respectively electrically connect theanalog-capability tester electrical contacts on tester board 42 to theanalog-capability device-side electrical contacts on device-side board46 in the same way as shown in FIG. 14. The analog-capability contacts,along with the associated analog-ground electrical contacts, are thusnormally metal pads. An arrangement largely identical to that of FIG. 14is also employed for connecting the ends of the analog-capabilityinterface conductors to the analog-capability tester and device-sidecontacts.

Analog ground potential normally needs to be a“quiet” ground. Digitalground potential may vary significantly compared to analog groundpotential. When interface module 44 is configured in the mannerdescribed above in conjunction with FIGS. 4-10 and ground connectionsare provided in the way just described, analog ground potential islargely isolated from digital ground potential. Hence, analog groundpotential in module 74 can be a quiet ground even if digital groundpotential is noisy.

Device-side body 52 in interface module 44 is physically coupled totester-side body 50 only by digital-capability interface conductors 54and the analog-capability interface conductors. These conductors arephysically moderately flexible. As indicated above, device-sideprotective posts 102 cooperate with tester-side flanges 62 to preventmodule 44 from being significantly distended during handling but do nottouch flanges 62 during normal test operation. As a result, theconfiguration of module 44 substantially inhibits any vibrations thatmay arise in test components 12, 14, and 16 from being transmitted todevice chamber 48 and disturbing the function of the non-intrusive probein chamber 48.

While the invention has beet described with reference to particularembodiments, this description is solely for the purpose of illustrationand is not to be construed as limiting the scope of the inventionclaimed below. For instance, the number of tester-side wedge-shapedportions 68 can be different from eight. In one aspect, the number ofwedge-shaped portions 68 is generally a multiple of 4, such as 8, 12,16, and so on, where 8 is the lowest multiple of 4. Each side of thegenerally annular square pattern formed by device-sidedigital-capability portions 108 is then normally associated with aplural number, e.g., 2, 3, 4, and so on, of tester-side wedge-shapedportions 68. Choosing the number of portions 68 in this mannerfacilitates repairing module 44 and enables the test system of FIG. 3 totest implementations of DUT 40 having an increased number of externalelectrical leads.

The repairability and increased lead-count advantages can also beachieved when there are as few as five tester-side wedge-shaped portions68, provided that the outer lateral periphery of wedge-shaped portions68 are, as a group, roughly shaped like a regular polygon having atleast five sides so that digital-capability openings 86 in portions 68form a pattern whose outer lateral periphery is likewise roughly aregular polygon having at least five sides. The base of each portion 68then forms one side of the polygon.

As briefly indicated above, the base of each tester-side wedge-shapedportion 69 can be significantly curved, e.g., circularly curved so thateach wedge-shaped portion is roughly shaped like a piece of pie. In thatcase, the outer lateral periphery of portions 68 is, as a group, shapedgenerally like a circle. For the situation in which tester-sidedigital-capability openings 86 largely fully occupy portions 68, theouter lateral periphery of the pattern formed by openings 86 is thenlikewise roughly a circle.

When the pattern of tester-side digital-capability openings 86 hasroughly a circular outer lateral periphery, the number of tester-sidewedge-shaped portions 86 can be reduced to four, or even three, eachportion 68 still being generally shaped like wedge. Four wedge-shapedportions 68 provide an attractive variation because four portionsmatches the number of sides in the generally square shaped typicallyformed by device-side digital-capability portions 108. Nonetheless, thenumber of portions 68 can even be reduced to two in certain cases. Whenthere are two portions 68, each portion 68 is generally shaped like ahalf moon rather than a wedge.

As the number of tester-side digital-capability portions 68 changes, thenumber of device-side digital-capability portions 108 typically changesin the same way. Device-side portions 108 can also be arranged so thatthe pattern formed by their outer lateral periphery significantlydiffers from a square. For instance, the outer lateral periphery ofdevice-side portions 109 can, as a group, be shaped generally like arectangle whose sides are not all of largely the same length.

It may, in some cases, be advantageous for the base of each device-sidedigital-capability portion 108 to be significantly curved, e.g.,circularly curved. Digital-capability portions 108 may, as a group, thenhave a generally circular outer lateral periphery. When device-sidedigital-capability openings 136 largely fully occupy digital-capabilityportions 108, openings 136 then form a pattern whose outer lateralperiphery largely matches the pattern of the outer lateral periphery,e.g., rectangular or even circular, of device-side digital-capabilityportions 108.

Additional analog test capability can be built into interface module 40by modifying bodies 50 and 52 to increase the size of cylindricaltester-side analog capability portion 66 and rectangular-shapeddevice-side analog-capability portions 106. This may, or may not,involve decreasing the size of wedge-shaped tester-sidedigital-capability portions 68 and trapezoidal-shaped device-sidedigital-capability portions 108.

The designation of the interface conductors that go through-openings 80in cylindrical tester-side portions 66 and through openings 132 inrectangular-shaped device-side portion 106 as analog-capabilityconductors is arbitrary. If DUT 40 is solely digital and has more than1024 external electrical leads for transmitting digital signals, theinterface conductors which go through openings 80 and 132 can beutilized for transmitting digital test signals to the extent that theadditional necessary digital test capability is not achieved with the 96conductors 54 allocated for supplying power and for unspecifiedpurposes.

The designation of interface conductors 54 as digital-capabilityconductors is likewise arbitrary. If DUT 40 is solely analog and hasmore than 32 external leads for transmitting analog test signals,conductors 54 can be employed for transmitting analog test signals. IfDUT 40 is largely analog and has no more than 32 external electricalleads for transmitting digital test signals, the digital/analog roles ofconductors 54 and the other 32 interface conductors can be reversed.Various modifications and applications may thus be made by those skilledin the art without departing from the true scope and spirit of theinvention as defined in the appended claims.

We claim:
 1. An interface module for situation between (a) a testermechanism having multiple electrical tester contacts for carryingelectrical test signals and (b) a device-side board having multipleelectrical device-side contacts for connection to external electricalleads of an electronic device under test, the module comprising: atester-side body comprising at least five physically separate generallywedge-shaped tester-side portions laterally arranged so that their tipsare directed generally toward one another, each tester-side portionhaving multiple tester-side openings suitable for being positionedrespectively opposite corresponding ones of the tester contacts; adevice-side body having multiple device-side openings suitable for beingpositioned respectively opposite the device-side contacts; and multipleelectrical interface conductors, each extending through one of thetester-side openings and through a corresponding one of the device-sideopenings for electrically connecting one of the tester contacts to acorresponding one of the device-side contacts.
 2. A module as in claim 1wherein the tester-side openings are arranged in a pattern whose outerperiphery is shaped generally like a circle or like a polygon having atleast five sides respectively corresponding to the tester-side portions,multiple ones of the tester-side openings in each tester-side portiondefining the corresponding side of the polygon.
 3. A module as in claim2 wherein the polygon is approximately a regular polygon.
 4. A module asin claim 1 wherein the number of tester-side portions is a multiple offour.
 5. A module as in claim 2 wherein the tester-side openings in eachtester-side portion are arranged in lines extending generally parallelto each other and generally toward the center of the circle or polygon,the tester-side openings in at least one pair of consecutive ones of thelines in each tester-side portion being staggered relative to oneanother.
 6. A module as in claim 1 wherein the device-side bodycomprises at least five physically separate device-side portionsrespectively corresponding to the tester-side portions, each device-sideportion having multiple ones of the device-side openings such that oneof the interface conductors passes through one of the device-sideopenings of that device-side portion and then through one of thetester-side openings of the corresponding tester-side portion.
 7. Amodule as in claim 6 wherein each tester-side portion, the correspondingdevice-side portion, and the interface conductors passing through theirtester-side and device-side openings form a unit which is removable fromthe module separately from each other such unit.
 8. A module as in claim6 wherein the device-side openings are arranged in a pattern whose outerperiphery is shaped generally like a rectangle.
 9. A module as in claim8 wherein the rectangular pattern of the outer periphery of thedevice-side openings is generally square.
 10. A module as in claim 6wherein the number of tester-side portions is a multiple of four, andthe number of device-side portions is also a multiple of four.
 11. Amodule as in claim 1 wherein the tester-side portions are largelyidentical to one another.
 12. A module as in claim 1 wherein thedevice-side body is physically coupled to the tester-side bodysubstantially only through electrical interface conductors which extendthrough openings in both the tester-side body and the device-side body.13. A module as in claim 1 wherein (a) the tester mechanism has multiplefurther electrical tester contacts for carrying further electrical testsignals and (b) the device-side board has multiple further device-sideelectrical contacts for connection to further electrical leads of thedevice under test and wherein: the tester-side body has multiple furthertester-side openings suitable for being positioned respectively oppositethe further tester contacts; the device-side body has multiple furtherdevice-side openings suitable for being positioned respectively oppositethe further device-side contact; the module further includes multiplefurther electrical interface conductors, each extending through one ofthe further tester-side openings and through a corresponding one of thefurther device-side openings for electrically connecting one of thefurther tester contacts to a corresponding one of the furtherdevice-side contacts.
 14. A module as in claim 13 wherein; the furtherinterface conductors are utilized in providing an analog testcapability; and the other interface conductors are utilized in providinga digital test capability.
 15. A module as in claim 13 wherein thedevice-side body is physically coupled to the tester-side bodysubstantially only through the interface conductors.
 16. A module as inclaim 1 wherein the device under test is an integrated circuit.
 17. Aninterface module for situation between (a) a tester mechanism havingmultiple electrical tester contacts for carrying electrical test signalsand (b) a device-side board having multiple electrical device-sidecontacts for connection to external electrical leads of an electronicdevice under test, the module comprising: a tester-side body havingmultiple tester-side openings suitable for being positioned respectivelyopposite the tester contacts, the tester-side openings being laterallyarranged (a) in a pattern whose outer periphery is shaped generally likea circle or like a polygon having at least five sides and (b) in linesdirected generally toward the center of the circle or polygon, thetester-side openings in at least one pair of consecutive ones of thelines being staggered relative to one another; a device-side body havingmultiple device-side openings suitable for being positioned respectivelyopposite the device-side contacts; and multiple electrical interfaceconductors, each extending through one of the tester-side openings andthrough a corresponding one of the device-side openings for electricallyconnecting one of the tester contacts to a corresponding one of thedevice-side contacts.
 18. A module as in claim 17 wherein, when theouter periphery of the pattern of the tester-side openings isspecifically shaped generally like a polygon, the tester-side bodycomprises at least five tester-side portions, each having multiple onesof the tester-side openings, multiple ones of the tester-side openingsin each tester-side portion defining a different corresponding one ofthe sides of the polygon, the lines of the tester-side openings in eachtester-side portion extending generally parallel to one another.
 19. Aninterface module for situation between (a) a tester mechanism havingmultiple electrical tester contacts for carrying electrical test signalsand (b) a device-side board having multiple electrical device-sidecontacts for connection to external electrical leads of an electronicdevice under test, the interface module comprising: a tester-side bodyhaving multiple tester-side openings suitable for being positionedrespectively opposite the tester contacts, the tester-side openingsbeing arranged in a pattern whose outer periphery is shaped generallylike a circle or like a polygon having at least five sides; adevice-side body having multiple device-side openings suitable for beingpositioned respectively opposite the device-side contacts, thedevice-side openings being arranged generally in a pattern whose outerperiphery is shaped generally like a rectangle; and multiple electricalinterface conductors, each extending through one of the tester-sideopenings and through a corresponding one of the device-side openings forelectrically connecting one of the tester contacts to a correspondingone of the device-side contacts.
 20. A module as in claim 19 wherein thenumber of sides of the polygon is a multiple of four.
 21. An interfacemodule for situation between (a) a tester mechanism having multipleelectrical tester contacts for carrying electrical test signals and (b)a device-side board having multiple electrical device-side contacts forconnection to external electrical leads of an electronic device undertest, the module comprising: a tester-side body comprising at least twophysically separate tester-side portions laterally arranged so thattheir outer lateral peripheries are, as a group, generally shaped like acircle, each tester-side portion having multiple tester-side openingssuitable for being positioned respectively opposite corresponding onesof the tester contacts; a device-side body having multiple device-sideopenings suitable for being positioned respectively opposite thedevice-side contacts; and multiple electrical interface conductors, eachextending through one of the tester-side openings and through acorresponding one of the device-side openings for electricallyconnecting one of the tester contacts to a corresponding one of thedevice-side contacts.
 22. A module as in claim 21 wherein thedevice-side body comprises at least two physically separate device-sideportions respectively corresponding to the tester-side portions, eachdevice-side portion having multiple ones of the device-side openingssuch that one of the interface conductors passes through one of thedevice-side openings of that device-side portion and then through one ofthe tester-side openings of the corresponding tester-side portion.
 23. Amodule as in claim 22 wherein each tester-side portion, thecorresponding device-side portion, and the interface conductors passingthrough their tester-side and device-side openings form a unit which isremovable from the module separately from each other such unit.
 24. Amodule as in claim 21 wherein the number of tester-side portions is atleast four, whereby the tester-side portions are generally wedge shaped.